1. Field of the Invention
The present invention relates to a toner conveying apparatus for conveying toner, and an image forming apparatus having the same.
2. Description of the Related Art
A conventional electrophotographic image forming apparatus has a developing apparatus that uses toner to develop an electrostatic latent image formed on a surface of an image bearing member. The developing apparatus has a conveyance path for conveying toner from a toner storage section to a toner supply section. The conventional electrophotographic image forming apparatus has a toner recovery apparatus that recovers excess toner remaining on the surface of the image bearing member after the toner image of the image bearing member is transferred. The toner recovery mechanism has a conveyance path for conveying toner. The inside of the conveyance path for conveying toner is configured to rotate a screw to convey toner.
Such toner conveying apparatuses each having a conveyance path for conveying toner are disclosed in Japanese Patent Application Laid-Open No. 2002-311712 and Japanese Patent Application Laid-Open No. 2005-258300. The toner conveying apparatuses disclosed in Japanese Patent Application Laid-Open No. 2002-311712 and Japanese Patent Application Laid-Open No. 2005-258300 are the invention relating to a toner conveying apparatus including a conveyance path for conveying toner; a rotatable rotating shaft located in one end portion of the conveyance path; and an agitation member eccentrically connected to the rotating shaft to agitate toner inside the conveyance path. Such a configuration can efficiently convey tone without aggregation or adhering of toner.
Unfortunately, according to the toner conveying apparatuses disclosed in Japanese Patent Application Laid-Open No. 2002-311712 and Japanese Patent Application Laid-Open No. 2005-258300, one end portion of the agitation member is eccentrically connected to the rotating shaft, but the other end portion of the agitation member is free, whereby the swing area of swinging the agitation member inside the conveyance path is limited.
FIG. 7 is an enlarged sectional view that explanatorily shows a feature of a swing area in which an agitation member can swing is restricted. As illustrated in FIG. 7, a toner conveying apparatus 525 is configured such that one end of an agitation shaft 60 (agitation member) eccentrically connected to a crank and the other end of the agitation shaft 60 is free. An upstream screw shaft 28a that is an end of an upstream screw shaft rotates a crankshaft 29 to swing the agitation shaft 60.
Thus, the agitation shaft 60 swings in a transverse direction (indicated by an arrow P) and in a longitudinal direction (indicated by an arrow Q) to prompt to convey toner on the bottom side of a conveyance case 27, but cannot cover the entire area inside the conveyance case 27 including toner on the ceiling surface side thereof as the agitation shaft movable area. As a result, a non-agitation area 59 (area enclosed by the one-dot chain line) remains.
Further, the agitation shaft 60 on a downstream end side performs only translational motion as indicated by an arrow Q, which generates a non-agitation area 59, which presses toner to move outside a movable area to adhere thereto, which may prompt, toner clogging.